Inducing Genetic Variability for Yield and Growth Traits in Kidney Bean (Phaseolus vulgaris L.) Using Physical and Chemical Mutagenesis

Abstract

Induced mutagenesis is a successful method for producing new genetic variability in self-pollinated crops with limited natural diversity. The current study assessed the impact of gamma radiation (10kR, 15kR, 20kR and 25 kR), ethyl methanesulfonate (EMS; 0.10%, 0.15%, 0.20% and 0.25%) and Sodium azide (SA; 0.010%, 0.015%, 0.020% and 0.025%) on two kidney bean cultivars, Varun and Waghya. The M₁ generation was assessed for germination, seedling height, leaf morphological mutations, chlorophyll chimeras, plant survival and yield-related traits under field conditions. All mutagenic treatments caused dose-dependent reductions in germination, seedling growth and survival, with SA producing the strongest phytotoxic effects. In contrast, leaf morphological mutations and chlorophyll chimeras increased with treatment intensity, with EMS at 0.20% and SA at 0.020–0.025% producing the highest mutation frequencies. Yield-related traits, including pod length, pods/plant & seeds/pod, declined moderately at higher doses, while seed size shifted toward smaller categories and seed coat colour varied within treatment groups. Varun showed higher mutability, whereas Waghya exhibited greater tolerance and relative stability. The study identifies promising mutagenic treatments for creating useful variability in kidney bean, while emphasizing that confirmation of stable, heritable mutants requires evaluation in M₂ and later generations.